Voltage regulator with hybrid control for fast transient response

Abstract

The present invention provides a voltage regulator including a voltage control circuit and a current control circuit. The voltage control circuit is configured to receive an output voltage of the voltage regulator to generate a first current to an output terminal of the voltage regulator; and the current control circuit is configured to generate a second current to the output terminal of the voltage regulator according to an output current of the voltage regulator, wherein the output current is generated according to the first current and the second current.

What is claimed is: 
     
       1. A voltage regulator, comprising:
 a voltage control circuit, configured to receive an output voltage of the voltage regulator to generate a first current to an output terminal of the voltage regulator; and 
 a current control circuit, configured to generate a second current to the output terminal of the voltage regulator according to an output current of the voltage regulator, wherein the output current is generated according to a combination of the first current and the second current. 
 
     
     
       2. The voltage regulator of  claim 1 , wherein the second current has a fixed ratio to the output current. 
     
     
       3. The voltage regulator of  claim 2 , wherein the second current is equal to N times the output current, and the first current is equal to M times the output current. 
     
     
       4. The voltage regulator of  claim 3 , wherein a summation of M and N is equal to 100%. 
     
     
       5. The voltage regulator of  claim 3 , wherein N is greater than M. 
     
     
       6. The voltage regulator of  claim 1 , wherein a loop of the voltage control circuit and a loop of the current control circuit are independent of each other. 
     
     
       7. The voltage regulator of  claim 6 , wherein the voltage control circuit comprises:
 an error amplifier, configured to compare a signal derived from the output voltage with a reference voltage to generate a control signal; and 
 a current generator, configured to generate the first current according to the control signal. 
 
     
     
       8. The voltage regulator of  claim 6 , wherein the current control circuit comprises a transconductance amplifier configured to receive a voltage signal generated according to the output current to generate the second current. 
     
     
       9. The voltage regulator of  claim 6 , wherein the current control circuit comprises:
 a resistor, coupled to the output terminal of the voltage regulator, wherein the output current flows through the resistor; and 
 a transconductance amplifier, configured to receive voltage signals at two terminals of the resistor to generate the second current. 
 
     
     
       10. The voltage regulator of  claim 9 , further comprising:
 an output capacitor, coupled between the output terminal of the voltage regulator and a reference voltage; 
 wherein the output capacitor and the voltage regulator are within a single package.